Well casing protector



Dec. 3, 1963 P. R. BIEDERMAN WELL cAsING PROTECTOR INVENTOR.

PAUL E. B/EDEEMAN Filed Dec. 26. 1961 E Vir, S Y lr n ff i I ATTORNEY United States Patent C) 3,1l2,961 WELL CASING PRTECTOR Paul R. Biedermann, 3325 Flower Drive, Los Angeles 37, Calif. Filed Dec. 26, 1961, Ser. No. 161,902 8 Claims. (Ci. 308-4) This invention pertains to a device primarily intended for protecting well casings from injury caused by tool joints during drilling.

In the process of drilling wells the casing is subject to damage from the tool joints of the rotating drill stem. The tool joints are of larger diameter than the drill pipe, and as the drilling takes place the joints can strike and rub against the casing. In the past it has been common practice, in an effort to alleviate this condition, to provide a protective bumper to preclude engagement between the tool joint and the casing. Generally, these devices have been in the form of a resilient sleeve fitted over the drill pipe adjacent the tool joint. Such a sleeve has an interior diameter less than the outside diameter of the drill pipe. For installation it is expanded by a special tool to iit over the collar and is intended to frictionally grip the exterior of the drill pipe.

Devices of this type have proved largely ineffective. This is because as the drill stem is rotated and the sleeves are brought into contact with the casing, they soon stretch and become loosened. This permits the protectors to slide along the pipe away from the tool joints. Hence, in a relatively brief period of time the protectors will be distended on the rotating drill stem and will travel away from the tool joints. Therefore, all protection is lost and the Well casing is again subject to damage from contact by the tool joints.

The device of this invention overcomes such diiculties by the use of a resilient sleeve having a metal band ernbedded within it. The unit is split axially with the free ends being secured together by a special drive pin arrangement. This device has several advantages, one of which is ease of installation and removal which may be eifected by hammer and screwdriver. Thus, the necessity for special equipment is avoided. Also, the metal band assures that the inner portion of the sleeve will be iirmly tightened around the exterior of the drill pipe and cannot expand and become loosened. Therefore, the resilient exterior of the sleeve can always act as a bumper in protecting the well casing. The invention finds added use outside of the well drilling field in providing a means for sealing breaks in fluid carrying pipes.

Therefore, an object of this invention is to provide an improved and more reliable arrangement for protecting well casings during drilling.

Another object of this invention is to provide a well casing protector that may be installed and removed without the use of special equipment.

A further object of this invention is to provide a well casing protector requiring a minimum amount of time for installation and removal.

Yet another object of this invention is to provide a well casing protector that firmly grips the exterior of the drill stem and is precluded from sliding along the length of the drill pipe.

An additional object of this invention is to provide a device readily usable in sealing leaks in pipes or conduits.

These and other objects will become apparent from the following detailed description taken in connection with the accompanying drawing in which:

FIG. 1 is an elevational view of a drill stem utilizing the protector of this invention,

FIG. 2 is an enlarged elevational View, partially broken away, showing the protector of this invention in a locked position,

B-,iilgi Patented Dec. 3, 1963 FIG. 3 is a fragmentary longitudinal sectional View, taken along line 3--3 of FIG. 2, illustrating the portion of the protector where the free ends of the sleeve are joined together,

FIG. 4 is a transverse sectional view of the protector taken along line 4-4 of FIG. 2,

FIG. 5 is a fragmentary transverse sectional view of a portion of the protector and the lock pin,

FIG. 6 is an elevational view of the protector in the released position with the lock pin removed, and

FIG. 7 is a transverse sectional view illustrating a modified form of the invention in which a hinge is included in the metal band.

With reference to FIG. l there may be seen a well casing 1 within which is inserted a rotatable drill stern 2. These drill stems commonly are made up of sections of drill pipe such as the lengths of pipe 3, 4- and 5 illustrated. Tool joints 6 and 7 are included at the junctures of the drill pipe sections 3, 4 and 5. These tool joints are of larger outside diameter than that of the lengths of pipe. Consequently, as the drill stem is rotated during drilling, the tool joints normally tend to contact the inner wall of the casing 1 to cause damage to the casing. This is precluded by the protectors 3 of this invention which are positioned on the drill stem 2 adjacent the tool joints 6 and 7 It may be seen that the protectors 3 have an outside diameter slightly larger than that of the tool joints 6 and 7, but smaller than the encompassing casing. By being positioned adjacent the tool joints the protectors will prevent the tool joints from engaging the well casing l.

With particular reference now to FIGS. 2, 3, 4 and 5, the protector 8 of this invention includes a sleeve 9 of resilient material, which may be an elastomer such as synthetic rubber. Embedded within the sleeve 9 is a sheet metal band i0. The latter member is interposed between the inner wall 12 and the outer wall 13 of the sleeve. Slots, perforations or the like llt are formed in the wall of the band 10 so that the rubber material of the sleeve passes therethrough, permitting the members 9 and 1t) to be constructed as a unitary element. In other words, the band 1i? is within an integrally bonded unit in which the perforations or slots permit the rubber on both sides to be securely held together. The radially extending edge portions 15 and i6 of the band lil are spaced inwardly from the radially extending end walls 17 and 18 of the sleeve 9.

The protector of this invention is split longitudinally at one portion of its circumference, thereby to provide a duality of free ends 20 and 21. The former is of bifurcated construction including upper and lower projecting portions 22 and 23, between which the tongue-like element 24 of the other edge section fits.

The band l0 is enlarged axially at the location of the split portion of the protector, extending substantially the full length of the sleeve 9 at the position of the ends 2@ and 2l. The ends of the band lt) are provided with apertures adapted to receive a lock pin 26 that serves to hold the protector together. Thus in the portion 24 of the tongue end 21 of the sleeve, there is a rearwardly bent section 27 secured to the remainder of the band by suitable means such as spot welds. This provides a longitudinal slot 28 through the end of this section of the element Iii. Similarly, there are provided doubled-over portions 29 and 30 at the other end 2t) of member l0, which segments also are secured in place by suitable means such as spot welding. The result is a duality of aligned end openings 3l and 32.

In use of the device of this invention the end sections 2t) and 2l initially are separated permitting the protector to be iitted over the drill stem 2 and positioned near a tool joint. Subsequently, the end sections 2t) and 21 are brought together, generally as indicated in FIG. 6. At this time, the lock pin 26 is inserted into the openings 28, 31 and 32. This may be accomplished without diiculty by forcing the drive pin downwardly from the top of the unit so that its end iirst passes through slot 31, then through opening 28, and finally into slot 32. When this occurs, the protector is locked firmly on the exterior of the drill pipe and the ends of the protector are secured together.

The locking and gripping action arises from the offset construction of the pin 26, which includes a central portion 34 that extends to one side of the aligned upper and lower portions 35 and 36. The overall width of this pin, which may be a relatively flat element as shown, is substantially the same as that of the apertures 28, 31 and 32. Therefore, as the bottom section 36 of the pin passes into the slot 2S, the longitudinal edge 37 of the portion 34 of the pin will bear against the edge 33 of the slot 3l. At the same time, the inclined edge 39 on the opposite side of the offset section of the pin (between portions 36 and 34), contacts the upper corner of edge 40 of the slot 2S. This results in a wedging action as the lock pin 26 enters the slots, thereby drawing the end portion 2i further within the bifurcated end section 20.

Additional wedging to tighten the joint occurs when the pin is advanced further into the openings. This movement of the pin brings longitudinal edge 41 of the central portion of the pin into Contact with edge 40, while inclined edge 42 engages the upper corner of edge 38. When the pin 26 is in its fully inserted position, the edges 4S and 44 of the top and bottom portions 35 and 36, respectively, engage the longitudinal walls 38 and 45 of the slots 31 and 32. Edge 41 of the central portion 34 of the pin contacts the longitudinal edge portion 40 of the central aperture 28. As a result, the ends of the sleeve are held together securely so that the inner wall 12 of the sleeve grips the exterior of the drill pipe with considerable frictional force. Preferably circumferential grooves 52 are included in inner wall 12 to increase the frictional force.

In order to hold the lock pin 26 in place an end shoulder 46 is provided at the upper end, and the opposite end 47 is adapted to be bent over, as best seen in phantom in FIG. 3. The end portion 47 may be of reduced thickness, as illustrated, to facilitate the bending of the end in this manner. This provides two shoulders that preclude inadvertent dislodging of the pin. The outer side edges of the pin should also be convergent, as shown, to facilitate entry of the pin into the openings 31, 2S and 32.

It can be seen, therefore, that installing the device of this invention requires no special tools or equipment and is accomplished in only a few moments of time. In view of the free ends of the sleeve, it can be fitted over the drill stem without diculty, and without the use of any expanding devices. Furthermore, the offset drive pin draws the end portions of the sleeve closely together so that ample frictional force is obtained between the inner wall 12 of the sleeve and the exterior of the drill pipe. The presence of the band permits this high frictional force to be realized, while also precluding expansion of the device during use. The inner wall 12 cannot become distended and enlarged as in conventional designs because it is held in place positively by the locked metal band 10. Nevertheless, there is ample wall thickness on the exterior of the band 1t) to provide complete protection to the well casing as the drill stem is rotated. The outer wall 13, therefore, acts as a bumper and always protects the casing from damage. Removal of the protector is as simple as its installation, being accomplished merely by driving the pin 26 out of the end section 20 and 21.

Even in instances where badly worn drill pipe is encountered, the device of this invention can be secured in place without the necessity for manufacturing special sizes. A shim of rubberized canvas, or similar material, is interposed between the inner wall of the sleeve and the outer surface of the worn pipe of slightly reduced diameter. This thin additional layer allows the unit to grip the pipe firmly as before.

In View of the use of elastomeric material, and the tight clamping force obtained by the device of this invention, it can be used also in repairing leaks in pipes or for other purposes. It serves to prevent fluid leakage when positioned around a pipe, and can be used also to couple separate sections together.

In some instances it may be preferred to modify the band construction slightly, as illustrated in FIG. 7. By this arrangement the band 48 is in two sections 49 and 50 secured together by a hinge 51 which is located diametrically opposite the locking portion of the unit. The presence of the hinge facilitates to some degree the opening up of the sleeve to fit it over the drill stem. In all other respects the arrangement of FIG. 7 may be similar to that of the previously described embodiment.

The foregoing detailed description is to be clearly understood as given by way of illustration and example only, the spirit and scope of this invention being limited solely by the appended claims.

I claim:

l. A well casing protector comprising a sleeve of resilient elastomeric material adapted to t over the exterior of a drill stem,

a sheet metal band embedded within said sleeve bctween the inner and outer walls thereof,

said band including opening means therethrough, said material extending through said opening means for providing a unitary structure with said band, said unitary structure being split longitudinally thereby to provide a duality of distal ends,

one of said ends being bifurcated thereby providing a duality of projecting end sections, the other of said ends including a tongue receivable between said sections, one end of said band extending into said end sections and being doubled over therein so as to provide a duality of longitudinally extending apertures, the other end of said band extending into said tongue and being doubled over therein so as to provide a longitudinally extending aperture through said tongue, a lock pin insertable through said apertures, said lock pin including aligned ends, an offset intermediate portion, and an inclined edge surface between one of said ends of said pin and said intermediate portion,

the overall width of said pin being substantially the same as the widths of said openings. 2. A device as recited in claim 1 in which said pin is longer than said sleeve,

said pin including a shoulder on one end thereof engageable with edge portions of said band, the opposite end of said pin being bendable for providing a second shoulder for thereby retaining said pin said openings.

3. A device as recited in claim 2 in which said band is in two sections and including hinge means pivotally interconnecting said sections at a location substantially opposite said distal ends.

4. A device as recited in claim 1 in which said sleeve is provided with groove means in the inner wall thereof for causing said sleeve to grip a drill stern with a high frictional force.

5. A well casing protector comprising a sleeve of resilient elastomeric material adapted to t around a drill stem,

a band of nonresilient material interposed between the inner and outer walls of said sleeve.

and

said sleeve and band being split axially so as to provide a duality of distal ends, one of said distal ends having a recessed portion provided with a duality of axially extending openings through said band and sleeve,

said openings being circumferentially elongated, the other distal end of said band and sleeve having a tongue adapted to fit within said recess in said other distal end, said tongue having an axially extending opening through said band and sleve,

said last mentioned opening being circumferentially elongated, and a lock pin insertable in said openings for securing said sleeve around a drill stem in frictional engagement therewith,

said lock pin having a rst longitudinal edge adapted to engage one side of said first-mentioned openings,

said longitudinal edge being laterally recessed at intermediate portions thereof to define an offset portion, the opposite edge of said offset portion extending laterally beyond the opposite edges of the end portions of said pin for engagement with the opposite wall of said opening in said tongue. 6. A device as recited in claim 5 in which said openings are of substantially the same width, and the overall width of said pin from said rst-mentioned edge of said end portions to said opposite edge of said olset portion is substantially the same as the width of said openings. 7. A well casing protector comprising a sleeve of resilient elastomeric material adapted to iit around a drill stern, a band of nonresilient material interposed between the inner and outer walls of said sleeve,

said sleeve and said band being split axially so as to provide a duality of distal ends, one of said distal ends being bifurcated and having an axially extending aperture in each portion of said bifurcated end, the other of said distal ends having a tongue adapted to iit within said bifurcated end, said tongue having an axially extending aperture therethrough, and a lock pin for securing said distal ends together, said lock pin having end portions in said apertures in said bifurcated end, and a laterally oiset central portion in said aperture in said tongue,

the width of said end portions and said central portion being less than the Width of said apertures in said distal ends, whereby upon insertion of said pin into said apertures said pin serves to draw said end portions of said sleeve and band together. 8. A device as recited in claim 7 in which said lock pin at one of said end portions is convergent outwardly at the longitudinal distal end thereof for facilitating entry of said pin into said apertures.

References Cited in the iile of this patent UNITED STATES PATENTS 1,965,998 Williams July 10, 1934 2,828,161 Whitney Mar. 25, 1958 2,897,016 Baker July 28, 1959 

1. A WELL CASING PROTECTOR COMPRISING A SLEEVE OF RESILIENT ELASTOMERIC MATERIAL ADAPTED TO FIT OVER THE EXTERIOR OF A DRILL STEM, A SHEET METAL BAND EMBEDDED WITHIN SAID SLEEVE BETWEEN THE INNER AND OUTER WALLS THEREOF, SAID BAND INCLUDING OPENING MEANS THERETHROUGH, SAID MATERIAL EXTENDING THROUGH SAID OPENING MEANS FOR PROVIDING A UNITARY STRUCTURE WITH SAID BAND, SAID UNITARY STRUCTURE BEING SPLIT LONGITUDINALLY THEREBY TO PROVIDE A DUALITY OF DISTAL ENDS, ONE OF SAID ENDS BEING BIFURCATED THEREBY PROVIDING A DUALITY OF PROJECTING END SECTIONS, THE OTHER OF SAID ENDS INCLUDING A TONGUE RECEIVABLE BETWEEN SAID SECTIONS, ONE END OF SAID BAND EXTENDING INTO SAID END SECTIONS AND BEING DOUBLED OVER THEREIN SO AS TO PROVIDE A DUALITY OF LONGITUDINALLY EXTENDING APERTURES, THE OTHER END OF SAID BAND EXTENDING INTO SAID TONGUE AND BEING DOUBLED OVER THEREIN SO AS 